“Today it was clear that Robert had Bayern in his heart,” Bild journalist Tobias Altschaffl quotes Heiner on Twitter.
The meeting in Munich ended with the score 2:0.
The goals were scored by Lucas Hernandez (50th minute) and Leroy Zane (54th).
The Polish footballer played for Bayern from 2014 to 2022.
In total, he played 253 matches for the club and scored 238 goals.
The striker moved from the Munich club to Barcelona for €45 million. The parties signed a four-year contract.
Earlier, Lewandowski expressed hope that he would not face Bayern in the Champions League group stage.